1. Field of the Invention
The present invention relates to a heat exchanger capable of exchanging heat between two kinds of fluids having different temperatures and humidities. More particularly, the invention is concerned with a heat exchanger which can perform, in ventilating an air-conditioned room or compartment of a house, automobile or the like, an exchange of heat between the outgoing air discharged to the outside and the incoming air introduced from the outside to thereby recover the heat which otherwise is carried away by the outgoing air to be wasted.
2. Description of the Prior Art
To comply with the demand stated above, the heat exchanger must be capable of exchanging heat in both aspects of actual heat and latent heat between the outgoing air and incoming air. Unfortunately, however, the conventional heat exchangers constructed with metals can make the exchange of the actual heat only. In consequence, the heat exchanging efficiency is undesirably lowered particularly when the latent heat occupies a large part of the total heat including actual heat and latent heat.
In order to overcome this problem, a heat exchanger has been proposed which incorporates a heat exchanging material having a low heat conductivity, such as asbestos, and impregnated with a moisture adsorbent, such as lithium chloride, thereby to recover the latent heat. This type of heat exchanger, however, is needs a complicated process of manufacture and thus is expensive.
Japanese Utility Model Publication No. 50-22365 (22365/1975) discloses a heat exchanger in which the heat is exchanged across a Japanese paper. The Japanese paper, although it can contribute to some extent to the exchange of latent heat, has poor heat transmitting and moisture permeating characteristics, so that the heat exchanging capacity of the heat exchanger is low relative to the size of the heat exchanger.
It is also to be pointed out that none of the heat exchangers proposed and used hitherto has a function to remove contaminants suspended by the incoming fresh air, so that the contaminated air is introduced into the room.